1. Field of the Invention
The present invention relates to a heavy duty "draw" or clamping type cabinet lock for securely releasably retaining a closure such as a relatively large cabinet door in its closed position. A lock embodying the preferred practice of the invention is particularly well suited for use with a cabinet (1) that is provided with gasketing and/or shielding to minimize penetration through the juncture of its closed door and its door frame of dust, moisture and/or interfering electromagnetic radiation, and/or (2) that needs its closure securely clamped closed at one or more locations about its closure opening.
2. Prior Art
Cabinet locks are known that are designed to releasably retain a closure in its closed position, and to effect engagement with and/or compression of closure seals including gasketing and shielding. However, these prior lock proposals have inadequately addressed a number of problems.
A problem that is encountered when locks are used with enclosures that house certain types of electronic equipment is that the cabinets and their doors must cooperate to provide an adequate degree of shielding against emission and absorption of interfering electromagnetic radiation. When such cabinets have doors that are quite large, locks are needed that are capable of clamping the doors and their associated cabinets securely together at a plurality of spaced locations along the doors in order for such seals and/or shields as are provided on these structures to function properly in blocking transmission of unwanted electromagnetic radiation. When such cabinets have doors that are small, locks that snugly clamp the closures closed at single locations along each closure will frequently fulfill requirements. Prior proposals have not yielded locks that adequately address typical needs of these types that are encountered with large and small specialty electronics enclosures.
Still another problem that is encountered with electronic equipment enclosures is that the types of seals that must be employed in order to provide adequate emissions shielding tend to resist not only door closing movements but also door opening movements. Some of these seals are positioned between a closed door and its door frame, and must be compressed as the doors are closed; others are arranged to frictionally engage portions of a door or its door frame as the door is closed. In order for doors to be closed and opened easily where such seals are in use, door locks are needed that have capabilities for forcefully moving doors both into and out of their closed positions, i.e., both toward and away from their associated cabinetry.
While a wide variety of proposals have been made to provide cabinet locks with desired features, there remains a need for a clamping type cabinet lock that can be easily adapted for use in a wide variety of installations, that is capable of effecting clamping of a closure at a single location or at a plurality of spaced locations about a closure opening to securely bias a closure toward a position of engagement with an associated opening-defining frame, and that is easily adjusted not only to accommodate installation tolerances and wear, but also to provide a closing action that is characterized by a desired degree of "draw" and by a clamping action that holds the closure closed with a desired degree of forcefulness.